On 06/18/2015 06:09 PM, Mauro Carvalho Chehab wrote:
> Instead of seeking for the decoder every time analog stream is
> started, cache it.
> 
> Requested-by: Hans Verkuil <hverk...@xs4all.nl>
> Signed-off-by: Mauro Carvalho Chehab <mche...@osg.samsung.com>
> ---
>  drivers/media/usb/au0828/au0828-video.c | 37 
> ++++++++++++++++++---------------
>  drivers/media/usb/au0828/au0828.h       |  1 +
>  2 files changed, 21 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/media/usb/au0828/au0828-video.c 
> b/drivers/media/usb/au0828/au0828-video.c
> index 4ebe13673adf..5f6e2aaad222 100644
> --- a/drivers/media/usb/au0828/au0828-video.c
> +++ b/drivers/media/usb/au0828/au0828-video.c
> @@ -641,32 +641,35 @@ static int au0828_enable_analog_tuner(struct au0828_dev 
> *dev)
>  {
>  #ifdef CONFIG_MEDIA_CONTROLLER
>       struct media_device *mdev = dev->media_dev;
> -     struct media_entity  *entity, *decoder = NULL, *source;
> +     struct media_entity  *entity, *source;
>       struct media_link *link, *found_link = NULL;
>       int i, ret, active_links = 0;
>  
>       if (!mdev)
>               return 0;
>  
> -     /*
> -      * This will find the tuner that is connected into the decoder.
> -      * Technically, this is not 100% correct, as the device may be
> -      * using an analog input instead of the tuner. However, as we can't
> -      * do DVB streaming while the DMA engine is being used for V4L2,
> -      * this should be enough for the actual needs.
> -      */
> -     media_device_for_each_entity(entity, mdev) {
> -             if (entity->type == MEDIA_ENT_T_V4L2_SUBDEV_DECODER) {
> -                     decoder = entity;
> -                     break;
> +     if (!dev->decoder) {
> +             /*
> +             * This will find the tuner that is connected into the decoder.
> +             * Technically, this is not 100% correct, as the device may be
> +             * using an analog input instead of the tuner. However, as we
> +             * can't do DVB streaming while the DMA engine is being used for
> +             * V4L2, this should be enough for the actual needs.
> +             */
> +             media_device_for_each_entity(entity, mdev) {
> +                     if (entity->type == MEDIA_ENT_T_V4L2_SUBDEV_DECODER) {
> +                             dev->decoder = entity;
> +                             break;
> +                     }

No, this is still searching unnecessary. Look in au0828_card_analog_fe_setup(),
which is where the au8522 is loaded (and that's the only decoder used by this 
driver):
just store the &sd->entity pointer in the decoder field and you're done. You can
drop this whole 'if (!dev->decoder)' part here.

BTW, the comment in the 'if' block belongs to 'for' loop below.

Regards,

        Hans

>               }
> +
> +             if (!dev->decoder)
> +                     return 0;
>       }
> -     if (!decoder)
> -             return 0;
>  
> -     for (i = 0; i < decoder->num_links; i++) {
> -             link = &decoder->links[i];
> -             if (link->sink->entity == decoder) {
> +     for (i = 0; i < dev->decoder->num_links; i++) {
> +             link = &dev->decoder->links[i];
> +             if (link->sink->entity == dev->decoder) {
>                       found_link = link;
>                       if (link->flags & MEDIA_LNK_FL_ENABLED)
>                               active_links++;
> diff --git a/drivers/media/usb/au0828/au0828.h 
> b/drivers/media/usb/au0828/au0828.h
> index 7e6a3bbc68ab..d3644b3fe6fa 100644
> --- a/drivers/media/usb/au0828/au0828.h
> +++ b/drivers/media/usb/au0828/au0828.h
> @@ -280,6 +280,7 @@ struct au0828_dev {
>  #ifdef CONFIG_MEDIA_CONTROLLER
>       struct media_device *media_dev;
>       struct media_pad video_pad, vbi_pad;
> +     struct media_entity *decoder;
>  #endif
>  };
>  
> 

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